Ask Slashdot: What's On Your Hardware Lab Bench? 215
50000BTU_barbecue writes "I made a comment a few days ago in a story basically saying the oscilloscope is dead. While that's a bit dramatic, I've found that over the last 20 years my oscilloscopes have been 'on' less and less. Instead, I use a combination of judicious voltage measurements, a logic analyzer and a decent understanding of the documentation of the gadget I'm working on. Stuff is just more and more digital and microcontroller-based, or just so cheap yet incredibly integrated that there's no point in trying to work on it. (I'm thinking RC toys for example. Undocumented and very cheap. Doesn't work? Buy another.) While I still do old-school electronics like circuit-level troubleshooting (on old test gear), that's not where the majority of hobbyists seem to be. Yet one thing I keep hearing is how people want an oscilloscope to work on hardware. I think it's just not that necessary anymore. What I use most are two regulated DC lab supplies, a frequency counter, a USB logic analyzer, a USB I2C/SPI master, and a USB-RS-232 dongle. That covers a lot of modern electronics. I have two oscilloscopes, a 100MHz two-channel stand-alone USB unit and a 1960s analog plug-in-based mainframe that is a '70s hacker dream scope. But I rarely use them anymore. What equipment do hardware folks out there use the most? And would you tell someone trying to get into electronics that they need a scope?"
An O'Scope (Score:5, Insightful)
If you're actually designing from scratch a new digital PCB, you can do without a lot of stuff but a 2GHz or faster O'scope is essential:
1) Debug of Switching Power Supplies [could get by with 100Mhz scope for this...]
2) Debug of high speed digital AC effects [line impendance, termination etc]
3) Verifying Setup / Hold of interface busses
4) Determining margin on variety of interfaces
Seriously. First tool a high speed scope... And Garmin International: 300MHz is for yesteryear, today most engineers need at least 1GHz to get by in digital design
2nd tool: a Good DMM
3rd tool: A thermal camera for when things go dreadfully wrong..
Other tools are gravy... [Though clearly a power supply is non-negotiable...]
Adapters. Lots of them. (Score:5, Insightful)
Every conceivable adapter, gender-bender, splitter, and breakout box under the sun.
Guiding principle: For every connector form, there is an equal and opposite requirement.
hardware (Score:5, Insightful)
10" table saw
craftsman drill press
Makita battery charger
2 vise, 1 with soft jaws
3 levels
bottle opener
Re:thats silly (Score:5, Insightful)
Indeed. If you do not need a scope, then you do not do any real electronics. For some debugging, there is no replacement. Especially for gaining understanding, nothing can replace it. And yes, mine is not on so often either, but for some things there is no replacement and I need it. Also, with a nice digital scope, you can document things by placing screen-shots on the web or into documents.
Scope usage (Score:4, Insightful)
I'm the author of Teensyduino, software for an Arduino compatible board.
I sometimes use my Agilent scope when developing or porting Arduino libraries. Sometimes I just want to check the relative timing of stuff, so I'll set a pin high or low at some point in the code, then capture with the scope to see if the code is taking a long time. Often it's surprising how fast, or how slow certain code can be, and pretty often it's relatively easy to discover and fix performance problems. You can do quite a lot by normal software debugging processes, but pretty much all those approaches involve running the code much slower. When you're debugging real-time code, like libraries that synthesize waveforms by bit-bashing or tricks with timers or DMA channels, there's really no substitute for a good scope.
But admittedly, this is a pretty narrow fringe. Most people probably don't do this sort of low-level coding.
Re:An O'Scope (Score:3, Insightful)
Cheap or not, that's not the criteria ... (Score:3, Insightful)
... when I am interested to know how one thing works
... when I just want to diagnose the inner-working of a gadget
I do not care how cheap that thing is, I'll power up my scopes
I do not care how cheap that thing is --- if I have to know I just have to know
I won't do the "oh, it's so cheap I'll buy a new one when this one conks", oh no, that's not the way I operate.
When my curiosity calls, I have to satisfy it.
Re:thats silly (Score:5, Insightful)
If only I had mod points...
Trust me on this one, you can spend your days in simulations all you want, but that >100Gb/s board isn't going to work if you can't check your rails and the jitter on your reference clocks.
If all you do is program other people's boards/systems, and they have enough shelf life already to be certified to work properly, then a scope isn't useful.
If you want to be near the cutting edge, you shouldn't fly blind.
Re:thats silly (Score:5, Insightful)
Obviously, anyone designing electronics and building prototypes needs a scope. How else would you know what the ground plane looks like? Clean or noisy? Even a cheap 20-40MHz scope will show dirty signals as "fussy", and will allow identification of beat patters and cyclic issues... I suspect the OP doesn't actually do any board design, because if he did he'd be using his scopes and spending big bucks on really good ones.
I suppose I don't do real electronics (Score:5, Insightful)
but that's a fair accusation, because I don't really.
80-90% of things can be shipped off to software where it's delightfully easy to trace/probe/debug things, and you have a functional unit which is infinitely malleable. What you can't do in software most realistically ends up in an FPGA, where really you're just debugging your VHDL/Verilog, and the simulator is your new best friend for 80-90% of the cases. When the simulator is a lying piece of junk, 80-90% of the time all you need is a good logic analyzer...
But there's still that ~1% of the time where software and/or digital logic just didn't behave right. Something analog is either necessary (e.g. maybe you're doing something actually useful, like driving a motor, rather than just flipping bits), or analog is making your life miserable.
Even professionally, I've found a 2-channel 50 MHz analog scope to be a godsend in some cases; of course, I like my 4-channel 1GHz digital scope more :) If you end up interacting with anything real and physical, or if you you move beyond merely debugging black boxes and into building your own stuff, even a crappy scope can give you information you simply can't get any other way. Who cares if it is uncalibrated and wildly inaccurate if a surplus scope will still show you the shape of what is going on, with all of the noise and ringing and transient under-(and over-)voltages and double bounces and cross-talk and odd harmonics and wtf why was that capacitor in the wrong bin this RC constant is borked and yep that part's dead and oh shit bad solder job and all the other crap that makes me happy I get to spend most of my time in nice clean software?
If you're just putzing around, sure, a DMM will do ya. But if you're actually building something new (even something simple), you need a scope.
Re:thats silly (Score:5, Insightful)
If you do not need a scope, then you do not do any real electronics.
I would say that's just a bit over-broad. For most digital work these days, you really just need a logic analyzer.
Having said that, if you are doing just about anything but "pure" digital work, do do pretty much need a scope.
I don 't think its a bit over-broad. I've had a scope probe in one hand since about 1950, and while you guys with the logic analysers will eventually find the problem IF you know what the signatures are telling you, some old fart like me with a scope probe in one or both hands, will find the problem and have it fixed while you are still consulting the schematic and hooking up your 16 channel logic analyser.
If you do not understand ALL the physics behind how all this stuff works, you are just a wannabe. Out in the real world, we are checking electrolytic caps for ESR first, then cracked "cold" solder joints or corroded IC pins. When you think you are good enough, go sit for a C.E.T. test, pass it with a 99% correct score, and then spend the next 40 years convincing the folks who write the checks that you can indeed walk on water. BTDT, still doing it occasionally at 79.